Evaluation of late blight-resistant small-fruited tomato cultivars and experimental hybrids on Long Island

摘要

The objective of this experiment was to evaluate late blight-resistant cultivars and experimental hybrids developed at Johnny's Selected Seeds (Winslow, ME). Seed of these entries as well as the susceptible entries included for comparison were provided by Emily Haga, Johnny's tomato breeder. The experiment was conducted at the Long Island Horticultural Research and Extension Center (LIHREC) in Riverhead, NY, in a field with Haven loam soil that has been dedicated to research on organically-produced crops since 2001. Organic fertilizer was spread over rows to be planted, then incorporated. Three products were used each at 700 lb/A: Pro-Grow 5-3-4, Cheep Cheep 4-3-3, and 6-0-6 Cottonseed blend on 5 May. Drip tape was laid as the rows were covered withblack plastic mulch. A living mulch was established by broadcasting a combination of annual ryegrass seed and clover seed with a hand-operated spreader between rows of plastic mulch, then lightly raking to incorporate on 21 May. The ryegrass plus weedsthat grew were mowed routinely. Some weeds were removed by hand. Tomato seed were sown in an organic seeding mix in the greenhouse on 9 May. Seedlings were fertilized with BioLink 3-3-3 organic liquid fertilizer beginning at the sight of the first true leaf and continued weekly until transplanted to the field. Seedlings were transplanted by hand on 14 Jun into holes opened in the plastic mulch by a waterwheel transplanter that also placed in the holes a starter fertilizer, Neptune's Harvest Benefits ofFish (2-4-1 N-P-K). A completely randomized block design with four replications was used. Plots consisted of 10 plants in a single row with 24-in. plant spacing and 68-in. row spacing. The ten plots in each replication were arranged in two adjacent rows.Following standard procedure for fresh-market tomato production on Long Island, plants were staked and trellised as they grew using the Florida weave trellising system with 4-ft stakes placed between plants. Water was provided as needed through drip tape laid beneath the plastic mulch. Thrips and tomato fruit worms were managed by applying Entrust (8 fl oz/A) on 16 and 23 Jul using a tractor-mounted boom sprayer equipped with twinjet (TJ60-11004VS) nozzles spaced 17 in. apart that delivered 68 gal/A at65 psi and 2.3 mph. Leaves were examined for symptoms of any foliar disease on 31 Jul, 16 Aug, 21 Aug, and 6 Sep. Late blight and other diseases observed were assessed by estimating the percentage of leaves in each plot with symptoms (incidence) and theseverity of symptoms on these affected leaves. Canopy severity was calculated by multiplying these values. Ripe fruit were harvested on 5, 16, 23, and 30 Aug. Fruit quality attributes assessed included taste rated on a 1-5 scale with 5 being excellent.Average monthly high and low temperatures (°F) were 78/61 in Jun, 86/71 in Jul, 80/64 in Aug, 74/57 in Sep, and 67/51 in Oct. Rainfall (inches) was 9.92, 3.07, 2.43, 2.62, and 0.19 for these months, respectively.